Content Settings: Add RevocationObserver to measure when permissions are revoked

chrome/browser/permissions/permission_manager.h

Index: chrome/browser/permissions/permission_manager.h
diff --git a/chrome/browser/permissions/permission_manager.h b/chrome/browser/permissions/permission_manager.h
index 79438b9ee74957bda1dec7431ddc17486b7ab07a..10144a8e1ad4e6d53d3b83722461522d354067ad 100644
--- a/chrome/browser/permissions/permission_manager.h
+++ b/chrome/browser/permissions/permission_manager.h
@@ -23,7 +23,8 @@ class WebContents;
 
 class PermissionManager : public KeyedService,
                           public content::PermissionManager,
-                          public content_settings::Observer {
+                          public content_settings::Observer,
+                          public content_settings::RevocationObserver {
  public:
   explicit PermissionManager(Profile* profile);
   ~PermissionManager() override;
@@ -86,6 +87,12 @@ class PermissionManager : public KeyedService,
                                ContentSettingsType content_type,
                                std::string resource_identifier) override;
 
+  // content_settings::RevocationObserver implementation.
+  void OnContentSettingRevoked(const GURL& primary_url,
+                               const GURL& secondary_url,
+                               ContentSettingsType content_type,
+                               std::string resource_identifier) override;
+
   Profile* profile_;
   PendingRequestsMap pending_requests_;
   SubscriptionsMap subscriptions_;